Valve



June 1959 c. J.IBISHOFBERGER 1 VALVE Fil ed May 10. 1954 R MR rm MW H 6 B IU- L R A c AND/WE) United States Patent C) M VALVE Carl J. Bishofberger, Minneapolis, Minn, assignor t Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application May 10, 1954, Serial No. 428,760

4 Claims. (Cl. 317-132) This invention relates to delayed action solenoid valves and, ,more specifically is directed to improvements in the type "of solenoid valves disclosed in copending patent applications of William J. McGoldrick, Serial No. 193,713, filed November 2, 1950, now abandoned, and of Carl J. Bishofberger, Serial No. 196,555, filed November 20, 1950, now Patent 2,735,644.

In delayed action solenoid valves of the type disclosed in the aforementioned patent applications, the coil member of the valves has connected in serial relationship therewith a thermistor or resistor member having a negative temperature coeificient of resistance so that as the coil and thermistor have potential applied thereto, the energization of the coil slowly builds up in accordance to the decrease in resistance of the thermistor. The amount of delay in obtaining full energization of the coil is dependent upon the characteristics of the thermistor, i.e., its initial resistance and the rate at which its resistance changes in accordance to current flowing therethrough. In general, the greater the initial resistance of the thermistor, the greater will be the delay before full energization of the coil is reached. In certain applications of delayed action solenoid valves, a relatively short delay of, for example, only a few seconds is sufiicient to achieve the desired result while in other applications a greater time delay is desired. It has been found that for solenoid valves wherein a greater time delay is desired, that the thermistor or resistor members dissipate more heat for each cycle of operation than do the thermistors used in the valves having the shorter delay. One of the reasons for this is that the initial or cold resistance of the resistors is higher than that of the resistors used in the valves having shorter delay and as the amount of current flowing through the coil needed for full energization thereof may be considered to be constant for any given size of both types of valves, it follows that for a full energization of the coil in the valve having the greater delay, a greater amount of power must be dissipated in its resistor. In structures of the type disclosed in the above identified patent applications, the heat dissipated by the resistor members causes an increase in the operating temperature of the coil members. This is due to the position of the thermistors with respect to the coils. It will be appreciated that the operating temperature of a coil is to a large extent a function of the current flowing through it. The coil temperature increases until the amount of heat dissipated therefrom equals the amount of heat generated within. However, when a thermistor is placed adjacent to the coil member, then the heat developed by the thermistor is transferred to the coil. This is because the thermistor normally operates at a higher temperature than the coil and thus the coil operating temperature increases. It has been found that in delayed action valves where an increased delay is desired, the temperature rise of the coil becomes excessive when the thermistors are so located. The present invention is directed to a means of thermally isolating the thermistor from the coil member so that the heat dissipated by the thermistor does not raise the temperature of the coil member to a point that would be objectionable. The invention further contemplates the positioning of the thermistor in such a way that the thermistor is near the portion of the housing for the coil that serves as a connection means between the housing and external conduit means or the like, which connection means and conduit means serve as additional heat radiating surfaces and thus effectively dissipate the heat generated by the thermistor in an efiicient manner. The invention further provides the thermal isolation of the thermistor from the heat of the coil. This feature allows the thermistor to cool off rapidly upon denergization so as to regain its original resistance in as short a time as is practical. Thus, if the valve is energized within a short time after deenergization, the thermistor will have cooled sufliciently so as to provide a proper time delay in the pull-in of the plunger. This feature is better understood when it is realized that while the coil member will normally operate at a lower temperature than the thermistor, its large mass cools more slowly than the thermistor and hence would tend, upon deenergization, to keep the temperature of the thermistor higher than the temperature at which it must be in order to provide the correct time delay. The thermistor is not only thermally remote from the coil, but is in good thermal contact wtih the relatively cool conduit connection means and conduit means so that upon deenergization, it cools off rapidly. However, at the same time, it is protected from drafts and injury from external sources which would adversely affect the device.

It is therefore one of the objects of this invention to provide an improved delay action solenoid valve.

A further object of the invention is to provide a means in a delayed action solenoid valve for effectively thermally isolating the thermistor means connected in circuit with the coil member of the valve so that the heat generated by the thermistor during the operation of the valve does not raise the operating temperature of the coil of the valve.

Another object of the invention is to orient the thermistor within the housing for the coil with respect to a conduit connection means on the housing so that the radiating ability of the conduit connection means and conduit means connected thereto may be utilized to dissipate the heat generated by the thermistor.

Another object of the invention is to thermally isolate the thermistor means from the coil means so that the coil with its large heat capacity does not retard the cooling ofl of the thermistor upon deenergization thereof thus promoting a consistent time delay of the device even for relatively rapid cycling of the device.

Still another object of the invention is to provide a means of mounting the thermistor so that while it is thermally remote from the coil means it still receives a maximum of protection against drafts and the like as well as injury caused by external forces such as workmen attaching conduit means or the like to the valve housing.

Other objects of the invention will be apparent from the drawing and from the following specification and claims.

In the drawing:

Figure 1 is a side elevational view in section of a delayed action solenoid valve embodying the teachings of my invention;

Figure 2 is a view in section of the valve shown in Figure 1 as seen along section lines 22 and which illustrates the details of the improved thermistor mounting means; and

Figure 3 is a detailed'view of the thermistor holding means as seen along section line 33 of Figure 2.

Referring to Figure l of the drawing, the solenoid Patented June 9, 1959' valvecomprises a valve body 11 having an inlet 12 and an outlet 13 and a valve seat 14 therebetween. A plug 15 seals an alternate inlet 12o, which may be used insteadof inlet 12, if it is so desired. Openings 12, 12a, and 13. have threaded. portions or other suitable means therein for connecting fluid conduit means, not shown. The valve body 11 has a stepped bore through a side wall thereof, coaxial with the valve seat 14. The stepped bore consists of an internally threaded bore 16 and an unthreaded, smaller diameter bore 17 extending inwardly from the bottom of bore 16 to the valve seat 14, and which forms a shoulder 18 between said bores 16 and 17. An annular groove 19 in the shoulder 18 has a sealing ring 20- therein for sealingly engaging a solenoid plunger tube assembly.

A nonmagnetic tube 21 has one of its ends extending through a washer 22, which is retained on said end by staking over said end as shown at 23, and/ or by brazing said washer to said end. Washer 22 and solenoid tube 21 are held against sealing ring 20 by a clamping nut 24 screwed into threaded bore 16. The other end of the tube 21 is closed'by a plug 25 of magnetic material, the plug being secured to the tube by brazing, welding or other means. The inner end of the plug 25 has an annular groove therein which holds a copper shading ring 27, while the other end of the plug has a threaded bore thereinto receive a machine screw 28.

A solenoid coil 29 slidably fits over and around the tube 21 and bears at its inner end against an insulation washer 30 and a washer 31 of magnetic material, which, in turn, abuts against the valve body. Positioned against the opposite end of the coil 29 is a second. insulation washer 32 and a secondmagnetic washer 33.

A cover member or housing 39 surrounds coil member 29 and is asymmetrically shaped with respect to the coil in that an elongation 39' of the cover defines a void space 41 (see Figure 2) between one end 43 of the cover and the coil 29. A spring washer 42 positioned between washer member 33 and the inside end surface of cover 39 serves to resiliently hold the washers 30, 31, 32 and 33 and coil 29 in assembled relationship. Cover 39 is secured to the coil and tube assembly by machine screw 28 which passes through suitable apertures in cover 39. and a name plate and engages the threaded bore of plug 25. A conduit fitting 45 is attached to end 43 of the cover 39 so as to provide a means of attaching the cover to conduit means 46, a portion of which is shown. A partition member 47 is secured to the insideof cover member 39 by spot welding or other suitable means and is located diagonally across the void space 41. An insulation member 48 abuts the surface of partition member 47 facing the coil 29. A slot 50 is provided in partition member 47 and extends from the bottom of the partition 47 longitudinally to a point near the. top thereof. A similar slot is provided in insulation member 48. Disposed in slot 50 are a pair of cooperable. thermistor enclosures 51 and 52 made out of a. ceramic or other suitable material, each of which has a longitudinal slot 53 along the outer surface there" of, slots 53 being slightly wider than the combined thickness. of partition 47 and insulation member 48 and of such a depththat whenmembers 51 and 52 are placed in back to back relationship, the assembly thereof may be inserted snugly into slot 50. The thermistor enclosures 51, and52 have semicylindrical recesses 54 therein so thatwhen the two members are placed in back to back abutting relationship, a cylindrical enclosure is providedfor a thermistor 55.0f the rod type. Members 51 and 52 have. additional notches 56 shown in Figure 3 whichprovideopenings between the hollow interior and the outside thereof and serve to provide a passageway fonleads connecting thermistor and coil member 29 in electrical series relationship To this end a connection lead 57, from an external source of power (not shown) is connected to one end of thermistor 55 while a second connection lead 58 is connected to one side of coil member 29, the other end of the coil being connected to the other end of thermistor 55 by lead 59. The heat generated in thermistor 55 by current passing therethrough is transmitted to the enclosure members 51 and 52 by conduction and radiation and the enclosure members 51 and 52 in turn conduct and radiate the heat to the portions of cover member 39 and which are in immediate proximity thereto. This for the most part is the portion 39' of cover member 39 which has conduit fitting 45 fastened integrally thereto and as above indicated conduit 46 is secured to the fitting 45. Thus the fitting 45 and the conduit 46 constitute an effective heat dissipation means and since most of the heat generated by thermistor S5 is transmitted to this portion of the cover, it follows that most of the heat will be dissipated ofi of the relatively cool conduit 46 and fitting 45 and therefore will not serve to appreciably increase the operating temperature of coil-member 29.

It will be appreciated that not only is the heat generated by thermistor S5 prevented from raising and oper ating temperature of coil 29, but the high heat capacity of coil 29 is ineffective in retarding the cooling 01f of thermistor 55 upon deenergization of the device. The thermistor 55 within enclosure 51-52, being in good thermal contact with the relatively cool end 39' of cover 39 as well as conduit connection means 45 and conduit 46, will cool ofi rather rapidly. Thus the resistance of thermistor 55 will increase toward its initial or cold starting resistance soon after deenergization, and thus be ready to provide a proper time delay in the pull-in of the valve upon subsequent energization thereof.

It will be further appreciated that while the thermistor S5 is effectively thermally isolated from coil 29 and in good thermal contact with end 39, it still is protected by the cover and conduit fitting from drafts which might adversely affect the operating characteristics of the valve. Further, the thermistor is protected from mechanical shock and injury in that it is firmly held in position with respect to the cover. Conduit fitting 45 has an internal shoulder 45' that prevents an unskilled workman from inserting an improperly, threaded pieceof conduit into void space 41 and injuring the thermistor 55.

A cup-shaped plunger 70, of magnetic material has a small coaxial thereof through which extends the stem of a headed pin '72 in engagement with the inner end of plug 25.. The other end of the plunger extends inwardly overthe peripheral edge of a flange 74. on acollar 75 to hold said flange against a shoulder in said other end of the-plunger. A valve havinga head 77 and a stem 78,which extends through the sleeve, isadapted to cooperate with the valve seat 14 to control the flow ofwfluid therethrough. The head has a sealing disc 80, positioned in a centrally disposed recess in saidhead, to providethe seal. Said disc 30 is retained insaidrecess in the head by means of a washer 81 overlying the peripheral edge of the disc, while the washer 81, itself, is retained in position by staking the peripherahedge ofthe head inwardly over the outer peripheral edge of the washer. 81. The stem 78 extends beyond the collar or sleeve 75 and carries an abutment washer 83 positioned inan annular groove near the end of the stern. It-is thus seen thatdue to the spacingbetween the abutment washer 83 and the adjacent end of' sleeve- 75, which provides a lost motion connection between said 1 valve and plunger 70, the plunger may move slightly away from thehead. 77 without causing any movement of the,valve sealingdisc 80. The disc is held against the valve-seat 14 and the outer end of headed pin 72 is held against plug 25 by means of a coil compression spring 84,position ed withinplunger and hearing at opposite ends thereof againstthehead of the pin and the-flange. It is thus seen ,that the plunger will be held against the head o f.the,va lve. andthe disc held in engagement with the seat by the same amount of bore 71 through the closed end force that the pin bears against the plug, as long as the plunger is substantially horizontal. A longitudinal slot 85 is provided in the side of the plunger which helps to prevent any dashpot action of the plunger in the tube as Well as preventing any undesired induced currents in the plunger.

While I have shown and described a specific embodiment of this invention, further modifications and improvements will occur to those skilled in the art. I desire it to be understood, therefore, that this invention is not limited to the particular form shown and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What I claim is:

1. A delayed action electromagnetic device comprising a coil, a housing for said coil, said housing being made of good heat conducting material and being asymmetrical with respect to said coil so that when said housing and said coil are in assembled relationship, a void space is defined therebetween, good heat conducting partition means on said housing separating said void space and said coil, holding means on said partition means, a thermistor positioned in said space by said holding means and connected in circuit with said coil, and means on said housing adjacent said space for connecting good heat conductive conduit means to said housing.

2. A delayed action electromagnetic device comprising a coil, a housing for said coil, said housing being asymmetrical with respect to said coil so that when said housing and said coil are in assembled relationship, a void space is defined therebetween, partition means on said housing separating said void space and said coil, slot means in said partition, enclosure means positioned in said slot means with substantially all of said enclosure means in said space, a thermistor positioned in said enclosure means and connected in circuit with said coil, and means on said housing adjacent said space for connecting heat conductive conduit means to said housing.

3. In a delayed action electromagnetic device, the combination comprising a coil, a thermistor in series with said coil, cover means made of good heat conductive material, means for connecting heat conductive means to said cover means, means attached to said cover means for supporting said thermistor, said supporting means being made of good heat conductive material and positioning said thermistor adjacent to said connecting means and providing a partition between said thermistor and coil so that said thermistor is thermally isolated from said coil means.

4. In a delayed action electromagnetic device, the combination comprising a coil, a thermally responsive resistor connected in series with said coil, 21 housing for said coil and said resistor, means for connecting heat conductive conduit means to said housing, and good heat conductive means within said housing for positioning said resistor so that said resistor is thermally isolated from said coil and is in thermal communication with said connecting means.

References Cited in the file of this patent UNITED STATES PATENTS 1,988,958 Patterson Jan. 22, 1935 2,083,387 Merrill June 8, 1937 2,114,961 Gille Apr. 19, 1938 2,222,419 McCarty Nov. 19, 1940 2,391,974 Hurwitz Jan. 1, 1946 2,458,123 Wasserlein Jan. 4, 1949 2,610,271 Russell Sept. 9, 1952 

